Liquid water transport mechanism in the gas diffusion layer

Zhou, Peng; Wu, Chengwei

doi:10.1016/j.jpowsour.2009.09.019

Cited by 56 publications

(27 citation statements)

References 34 publications

(54 reference statements)

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“…Since liquid water transport is assumed to be driven by hydraulic pressure [13], liquid permeability measurements [7] of the GDLs were carried out. As revealed in Figure 4, 25 BL shows a much higher liquid water flux at a given pressure than the 25 BC GDL.…”

Section: Gas Liquid Water and Water Vapour Transport Propertiesmentioning

confidence: 99%

“…A number of studies were recently conducted based on computer modelling approaches or in-situ water imaging with x-ray or neutron radiography in order to arrive at a deeper understanding of the mechanisms underlying water transport in GDLs [12]. A simple description based on capillary-driven flow only was concluded to be insufficient to predict liquid water transport in porous diffusion media, because in this case continuous liquid water flow from the site of high saturation to the areas of lower water saturation would occur [13]. This is why continuous water flow has never been observed in practice.…”

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confidence: 99%

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Mitigation of Water Management in PEM Fuel Cell Cathodes by Hydrophilic Wicking Microporous Layers

2010

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This study introduces a novel strategy for enhancing the performance of Polymer Electrolyte Fuel Cells at high current densities by means of an advanced gas diffusion layer design. The incorporation of hydrophilic wicking agents into microporous layers of the cathode gas diffusion layer improves water management, thus increasing the maximum power density of Polymer Electrolyte Fuel Cells. Ex-situ measurements with respect to water and vapour transport, and electrochemical polarisation data provide evidence suggesting that the beneficial effect has to be attributed to enhanced liquid water removal through the microporous layer.

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Section: Gas Liquid Water and Water Vapour Transport Propertiesmentioning

confidence: 99%

mentioning

confidence: 99%

Mitigation of Water Management in PEM Fuel Cell Cathodes by Hydrophilic Wicking Microporous Layers

2010

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“…Discrete models are often pore network models. Pore network models are very helpful for understanding the general dependencies of the liquid water transport phenomena in porous materials for fuel cells [17][18][19][20][21][22][23]. In contrast to continuum models, they are able to capture the complex liquid water fingering transport processes, observed in ex situ experiments for highly porous and hydrophobic materials [10,24].…”

Section: Introductionmentioning

confidence: 99%

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Alink

Gerteisen

2013

Energies

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In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM) fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL) structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

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“…[1][2][3][4] Common GDL types consist of porous carbon fiber-based materials with carefully adjusted water transport and storage capacities. The transport mechanism of two-phase flow in porous media was the subject of numerous theoretical [5][6][7][8][9] and experimental 10,11 studies. Especially, neutron and X-ray imaging techniques turned out as powerful tools for the investigation of water in porous materials like GDLs.…”

Section: Introductionmentioning

confidence: 99%

A dedicated compression device for high resolution X-ray tomography of compressed gas diffusion layers

Tötzke

Manke

Gaiselmann

et al. 2015

Review of Scientific Instruments

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We present an experimental approach to study the three-dimensional microstructure of gas diffusion layer (GDL) materials under realistic compression conditions. A dedicated compression device was designed that allows for synchrotron-tomographic investigation of circular samples under well-defined compression conditions. The tomographic data provide the experimental basis for stochastic modeling of nonwoven GDL materials. A plain compression tool is used to study the fiber courses in the material at different compression stages. Transport relevant geometrical parameters, such as porosity, pore size, and tortuosity distributions, are exemplarily evaluated for a GDL sample in the uncompressed state and for a compression of 30 vol.%. To mimic the geometry of the flow-field, we employed a compression punch with an integrated channel-rib-profile. It turned out that the GDL material is homogeneously compressed under the ribs, however, much less compressed underneath the channel. GDL fibers extend far into the channel volume where they might interfere with the convective gas transport and the removal of liquid water from the cell.

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Liquid water transport mechanism in the gas diffusion layer

Cited by 56 publications

References 34 publications

Mitigation of Water Management in PEM Fuel Cell Cathodes by Hydrophilic Wicking Microporous Layers

Mitigation of Water Management in PEM Fuel Cell Cathodes by Hydrophilic Wicking Microporous Layers

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

A dedicated compression device for high resolution X-ray tomography of compressed gas diffusion layers

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